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AFE4403EVM Hardware
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5.1
Power Supply
AFE4403 can operate from 2.0- to 3.6-V Rx analog supply (RX_ANA_SUP), 2.0- to 3.6-V Rx digital supply
(RX_DIG_SUP), 3.0- to 5.25-V Tx Control supply (TX_CTRL_SUP) and LED driver supply
(LED_DRV_SUP).
The power for the board is derived from the USB input (J4) through a forward-biased diode (D5) to avoid
reverse current flow. The USB data bus is ESD protected using TI’s ESD protection diode array
TPD4E004DRYR (U7). The USB VBUS is fed to the integrated Li-ion linear charger and system power-
path management module, BQ24032ARHLR (U12), which generates greater than 4.2-V output
(VCC_BAT). This output is fed to TI’s low-input boost converter with integrated power diode and
input/output isolation, TPS61093 (U9), for generating a boosted voltage of 8.97 V. This output is fed to
low-noise voltage regulator LP3878-ADJ (U8) for generating 5 V for the LED_DRV_SUP and
TX_CTRL_SUP. The boost converter output is also fed to the ultralow-noise linear voltage regulator
TPS7A4901DGN (U13) for generating 3 V for the RX_ANA_SUP and RX_DIG_SUP. The boost converter
output is also fed to the ultralow-noise linear voltage regulator TPS7A4901DGN (U14) for generating 3 V
for MSP_DVCC and MSP_AVCC.
Test point and series jumper resistors are provided to make sure the power supplies to the board are
correct. The corresponding voltages on AFE4403EVM are given in
Table 2
.
Table 2. Test Points for Measuring Voltages on the AFE4403SPO2EVM
S. No.
Test Point
Description
1
TP36
5 V
2
R76
5 V
3
R65
5 V
4
R55
3 V
5
R54
3 V
6
L3, pin # 2
3 V
5.2
Clock
The EVM has the option to use the on-board 8-MHz crystal or the clock for the AFE4403 from the
MSP430. The EVM is shipped to use the on-board 8-MHz crystal. The 4-MHz buffered output clock from
the AFE4403 can be accessed through an accessible via labeled CLKOUT.
5.3
Accessing AFE4403 Digital Signals
AFE4403 SPI interface and other digital signals with MSP430 can be accessed through the series resistor
jumpers given in
Table 3
.
Table 3. AFE4403 Digital Signals
S. No.
Signal
Jumper Resistor
1
STE
R29
2
SIMO
R31
3
SOMI
R33
4
SCLK
R35
5
ADC_RDY
R26
6
DIAG_END
R38
7
AFE_PDNZ
R42
5.4
USB Interface
The EVM has a micro-USB interface for PC application connectivity requiring a standard micro-USB to
USB cable for connection. AFE4403EVM is designed to work in the slave mode.
30
AFE4403 Development Guide
SLAU572B – June 2014 – Revised July 2014
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